May Newsletter 2013 - Light/Lux Meters, Is your office a dull place? Take the test!

May Newsletter 2013 - Light/Lux Meters, Is your office a dull place? Take the test!

In this month’s newsletter we run you through Lux Meters, what they do, why they are used as well as showing you how to conduct a OH&S Light study around your workplace.  For a bit of fun we took a couple of light meters out and about and tested the light levels at a few locations with some surprising results.  See below!

We would like to welcome Miriam to the Instrument Choice Team. Miriam started with us recently and is responsible for updating product information on our website.  She has hit the ground running and recently added the Sper Scientific AquaShock range of products to our website, the products also have very informative and interesting demo videos on the product pages, stock will be arriving in next week.  If you have any suggestions about information you would like to see on our website or you would just like to join us in welcoming Miriam to the team you can email her at [email protected].

A couple of our team members participated in the Colour Run recently, raising money for the Make a Wish Foundation and having a blast at the same time, you can see some very colourful photos of their day on our Facebook page.

Stay tuned to our Facebook page in the coming weeks as we have a very special announcement to make, let’s just say that we will be ‘expressing’ our thanks to our wonderful customers.

Remember; if you have any questions regarding tests you need to conduct or specific instrumentation please give us a call. 

Until next month...
Tyson Grub

And then there was light.  But how do you measure it?
Lux meters, or light meters, are meters that are used to measure light intensity. Common applications include measuring light intensity in workplaces, on roads,  walkways and in car parks.  

In workplaces, these tests are performed to make sure that the areas meet OH&S guidelines so that people can work safely. If light levels are too low, people may not be able to operate safely (i.e. missing steps on the stairs, eye strain, headaches). Similarly, if lux levels are too high, glare and reflected light can cause distraction, headaches and can impair vision. Different tasks require different illuminance levels, for example, the light levels in a corridor would not need to be as high as in an area where machinery is being used.

Lux meters will typically measure illuminance in Lux and sometimes footcandles, however this term is only really used in the US. One lux is equal to one lumen per square meter and the lumen is a measure of luminous flux. Typical starlight would have a value around 0.001 lux, an overcast day would be around 5000 lux, and a bright Australian summer day would be around 100,000 lux. Basic lux meters, such as the  Testo-540 will measure the current lux levels and store a maximum and minimum reading. Another example of a basic but highly functional meter is the LX-1108, with inbuilt settings for different lighting types, giving more accurate readings in different light sources.  These types of Lux meters are generally suitable for most OH&S requirements. 

Higher end units such as the IC-LX200  have a higher accuracy, data logging capabilities and can also be used to perform illuminance cartography which allows you to easily see and analyse how lighting levels vary across a work site or area
Test-Workspace-Lux-Email (1)
Is your office a dull place? Take the test!
For this experiment we will be measuring the lighting levels within a section of the Instrument Choice offices in various locations to ensure they meet the Safe Work Australia guidelines

These guidelines ensure that workers can operate safely without straining their eyes or having to adopt awkward postures within the workplace. For a bit of fun we will also send some members of our team out to check levels in random locations around town.
Safe Work Australia have released guidelines for recommended workplace illumination levels and these have been tabulated below, more details can be found here.

Class of task

Recommended Illuminance (lux)

Examples of types of activities/areas

Movement and Orientation


Corridors, walkways

Rough intermittent


Change and locker rooms, loading bays

Normal range of tasks and workplaces



Waiting rooms, lunch rooms, entrance halls, store rooms, meeting rooms

Ordinary or moderately easy


Food preparation, counters for transactions, computer use

Moderately difficult


Routine office tasks (eg. Reading, writing, typing)



Drawing boards, most inspection tasks, colour matching

Very Difficult


Fine inspection work, colour matching of dyes

Safe Work Australia also recommends that the following factors should be taken into account when determining if lighting levels are appropriate:

               The nature of the work activity being undertaken
               Illumination levels from both natural and artificial lighting
               The types of hazards present within the workplace
               Glare on worker’s computer screens (To determine glare from overhead lights on computer screens, an object such as a book should be placed above the eyes of the worker at eyebrow level. The worker should then establish whether the screen becomes clearer in the presence of overhead glare).
               Reflections on work surfaces (This can be determined by having the worker hold an object such as a book above the surface of their desk in order to see if this results in a change to the reflected glare from the screen).

Initially we did a walk through of the premises to determine the nature of the work being undertaken, the hazards present, and whether the computer screens in use were affected by glare or reflections. This was established by asking workers questions and having them perform the glare and reflections tests as per the methods described above. These results were then documented and are detailed later in the report.

Figure 1 - My colleague Tim performing the glare test


Using a Testo540 lux meter we then set about conducting our measurements to determine the relevant lux levels. The Testo540 was used as it is adapted to the spectral sensitivity of the eye and it comes with a calibration certificate from the manufacturer stating it has been calibrated to ISO:9001 standards at the time of production.

To take a measurement the meter was turned on and held horizontally at arm’s length (so that the Scientist’s body didn’t affect the lux reading) and held in place until the reading stabilised. Measurements were taken and noted at 3 points across each working surface. 

The measurements were taken at the height the majority of the work is undertaken within that area which was 760mm (table height) in our lunch room and conference room, 900mm (working height) in the kitchen, and 1300mm (eye height) in the offices. The walkthrough and measurements took approximately 45 minutes to undertake and could be undertaken in a similar timeframe within your workplace (depending on size). A site plan showing the location and lux value of each area along with an image of a measurement being undertaken are shown below:

Figure 2 - Lux levels in various locations in a section of Instrument Choice.

Figure 3 - Taking a lux measurement in the kitchen

The walk through and averaged lux level results are detailed in the following table:          


Nature of activity/or purpose of area




Lux level (lx)

Within recommended Guideline range?

Desk 1

Computer work

None present

Not present

Not present



Desk 2

Computer work

None present

Not present

Not present





None present





Conference room

Meetings, waiting room

None present





Staff Room

Lunch area

None present






Food preparation

None present





The results from our audit show that our lighting levels are within the recommend range as per the guideline. This means that all staff members should be able to perform their duties safely and without the need to strain their eyes or adopt an awkward posture.

Now that the heavy stuff is out the way, we can look at the fun locations around town that staff members from Instrument Choice measured. Some of them were quite surprising.

Figure 4 - Physiotherapist’s office , quite a low value considering they expect people to read while waiting.

Figure 5 - This supermarket has a lux level that makes finding their specials an easy task for anyone.

Figure 6 - This local Restaurant had a very low lux level of 11; ‘mood lighting’ certainly comes to mind here.

Figure 7 - Fresh fruit shop with a good lux level to show off their fabulous produce.

Figure 8 - Hockey Pitch located in Southern Adelaide produced a level of 3325 lux in the late afternoon, plenty high enough to see a fast shot at goal.

Figure 9 - The sunrise through a gap in the trees overlooking the south. What a perfect view to start the day (measured with LM8000)